Constitutive expression of the urokinase plasminogen activator gene in murine RAW264 macrophages involves distal and 5' non-coding sequences that are conserved between mouse and pig.

The 5' flanking regions of the mouse and pig urokinase plasminogen activator (uPA) genes were sequenced and sequence homology interrupted by repeat elements was found to extend to -4.6kb in pig and -6.6kb in mouse.

Expression of active yeast pyruvate decarboxylase in Escherichia coli.

We have shown by appropriate modification of the translational signals and using the strong T7 RNA polymerase promoter phi 10, that a cloned Saccharomyces cerevisiae pyruvate decarboxylase gene (pdc1) can be expressed in Escherichia coli. This protein, which migrated as a single band on SDS-polyacrylamide gels, was found to have a subunit molecular mass of approximately 62 kDa, similar to that of the enzyme produced by yeast. Polyclonal antibodies raised against purified yeast pyruvate decarboxylase recognized this bacterially produced protein.

A melanoma octamer binding protein is responsive to differentiating agents.

Analysis of human melanocytes and melanoma cell lines for proteins interacting with the octamer control sequence (ATGCAAAT) has revealed two distinct melanoma octamer binding proteins, Oct-M1 and Oct-M2. The latter was restricted to cell lines derived from tumor metastases. The level of Oct-M1 activity in a pigmented melanoma line was enhanced in comparison to the general octamer binding protein Oct-1 when cells were cultured in the presence of the depigmenting agent dithiothreitol and conversely was reduced by the differentiating and pigment inducing agents butyric acid and dimethyl sulfoxide.

Proliferin, a prolactin/growth hormone-like peptide represses myogenic-specific transcription by the suppression of an essential serum response factor-like DNA-binding activity.

Proliferin (PLF), a protein which has homology to PRL and GH, has been implicated in the regulation of cell growth and differentiation. PLF1 was detected and found to be differentially regulated during myogenesis in the rodent myogenic cell line C2C12. Transient and stable constitutive high level expression of PLF1 repressed expression of the transfected cardiac and skeletal alpha-actin myogenic-specific promoters, but did not affect expression of the cytoskeletal beta-actin and several viral promoters linked to CAT.

Characterisation of a Pseudomonas aeruginosa twitching motility gene and evidence for a specialised protein export system widespread in eubacteria.

Type-4 fimbriae (pili) are associated with a phenomenon known as twitching motility, which appears to be involved with bacterial translocation across solid surfaces. Pseudomonas aeruginosa mutants which produce fimbriae, but which have lost the twitching motility function, display altered colony morphology and resistance to fimbrial-specific bacteriophage. We have used phenotypic complementation of such mutants to isolate a region of DNA involved in twitching motility.

Gene sequences and comparison of the fimbrial subunits representative of Bacteroides nodosus serotypes A to I: class I and class II strains.

We have determined the nucleotide sequences of the genes encoding the fimbrial subunits representative of the known Bacteroides nodosus serogroups. All of the genes are preceded by a highly conserved region which includes the likely promoter and transcriptional regulator sites as well as the ribosome-biding site, and are followed within a short but variable distance by a sequence with the characteristics of a transcription termination or attenuation signal. Based on sequence and organization, the subunits can be divided into two major classes called I (serogroups A, B, C, E, F, G, and I) and II (serogroups D and H).

Organization of the fimbrial gene region of Bacteroides nodosus: class I and class II strains.

The fimbrial subunit genes of Bacteroides nodosus may be divided into two distinct classes, based on the sequence of the major subunit gene fimA (accompanying paper--Mattick et al., 1991). The genetic organization of the fibrial gene region in these two classes is also distinct.

A method for the stabilisation of recombinant plasmids in yeast.

The stability of a yeast plasmid can be improved using deliberately induced cyclic changes in the dissolved oxygen tension (DOT), during continuous culture in a non-selective, undefined medium. The resultant stability of the plasmid under DOT cycled conditions is strongly dependent on the growth rate of the culture, with complete stabilisation at lower growth rates. We propose a mechanism for the stabilisation and suggest that the method can be applied to other recombinant yeast strains.

Activation of macrophages to express cytocidal activity correlates with inhibition of their responsiveness to macrophage colony-stimulating factor (CSF-1): involvement of a pertussis toxin-sensitive reaction.

Bone marrow-derived murine macrophages were used to study the relationship between the proliferative response of macrophages to macrophage colony-stimulating factor (CSF-1) and their activation for cytocidal activity against tumour cells. Macrophage activation required two sequential signals. Lymphokines (gamma interferon, interleukin-4) provided the first (priming) signal; bacterial products (lipopolysaccharide, lipophilic muramyl tripeptide, lipopeptide 31362, pertussis toxin) provided the second (triggering) signal.